CATWOE

‘CATWOE’ is a mnemonic for a checklist for problem or goal definition (Checkland and Scholes, Soft Systems Methodology in Action, 1990). CATWOE is applied to the system which contains the problem, issue or solution, rather than to the problem or goal itself – i.e. to: ‘A system to ...’ ‘A system for ...’; or ‘A system that ...’. Such a definition should include:

C The ‘customers of the system’. In this context, ‘customers’ means those who are on the receiving end of whatever it is that the system does. Is it clear from your definition who will gain or lose?

A The ‘actors’, meaning those who would actually carry out the activities envisaged in the notional system being defined.

T The ‘transformation process’. What does the system do to the inputs to convert them into the outputs.

W The ‘world view’ that lies behind the root definition. Putting the system into its wider context can highlight the consequences of the overall system. For example, the system may be in place to assist in making the world environmentally safer, and the consequences of system failure could be significant pollution.

O The ‘owner(s)’ – i.e. those who have sufficient formal power over the system to stop it existing if they so wished (though they won’t usually want to do this).

E The ‘environmental constraints’. These include things such as ethical limits, regulations, financial constraints, resource limitations, limits set by terms of reference, and so on.

Just working through CATWOE, adding each element as you go, can lead to an unwieldy definition. It may be better to look at which are the important elements of CATWOE for any given system and use the relevant sub-set.